Hosted virtual server services allow users to instantiate virtual servers running software specified by the users without requiring a customer to own or manage the hardware underlying the virtual server instances. Virtual server services, including, for example, Amazon EC2, may enable users to instantiate a number of virtual servers of a variety of different configurations to match their needs.
Many virtual server services allow instantiation of virtual servers from bootable images provided by users. These images may contain the set of desired server software of the users. However, these virtual server images may require substantial time and effort to build, even when only minor changes to a virtual server's functionality are sought.